Fix NPE in ModelUtils getType

modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java

@@ -2128,7 +2128,7 @@ public static String getType(Schema schema) {
         }
 
         if (schema instanceof JsonSchema) {
-            if (schema.getTypes() != null) {
+            if (schema.getTypes() != null && !schema.getTypes().isEmpty()) {
                 return String.valueOf(schema.getTypes().iterator().next());
             } else {
                 return null;

modules/openapi-generator/src/test/resources/3_1/java/petstore.yaml

@@ -665,6 +665,47 @@ paths:
       responses:
         '200':
           description: Successful Response
+  "/fake/inline/schema/anyof/path1":
+    get:
+      tags:
+        - fake
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                anyOf:
+                  - type: 'null'
+                  - "$ref": "#/components/schemas/myObject"
+  "/fake/inline/schema/anyof/path2":
+    get:
+      tags:
+        - fake
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                anyOf:
+                  - "$ref": "#/components/schemas/myObject"
+                  - type: 'null'
+  "/fake/inline/schema/anyof/path3":
+    get:
+      tags:
+        - fake
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                anyOf:
+                  - type: array
+                    items:
+                      "$ref": "#/components/schemas/myObject"
+                  - type: 'null'
 externalDocs:
   description: Find out more about Swagger
   url: 'http://swagger.io'
@@ -981,3 +1022,5 @@ components:
     AllOfSimpleModel:
       allOf:
         - $ref: '#/components/schemas/SimpleModelWithArrayProperty'
+    myObject:
+      type: object

samples/client/petstore/java/okhttp-gson-3.1/README.md

@@ -93,10 +93,10 @@ public class Example {
 
     FakeApi apiInstance = new FakeApi(defaultClient);
     try {
-      Object result = apiInstance.op1();
+      Object result = apiInstance.fakeInlineSchemaAnyofPath1Get();
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#op1");
+      System.err.println("Exception when calling FakeApi#fakeInlineSchemaAnyofPath1Get");
       System.err.println("Status code: " + e.getCode());
       System.err.println("Reason: " + e.getResponseBody());
       System.err.println("Response headers: " + e.getResponseHeaders());
@@ -113,6 +113,9 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
+*FakeApi* | [**fakeInlineSchemaAnyofPath1Get**](docs/FakeApi.md#fakeInlineSchemaAnyofPath1Get) | **GET** /fake/inline/schema/anyof/path1 | 
+*FakeApi* | [**fakeInlineSchemaAnyofPath2Get**](docs/FakeApi.md#fakeInlineSchemaAnyofPath2Get) | **GET** /fake/inline/schema/anyof/path2 | 
+*FakeApi* | [**fakeInlineSchemaAnyofPath3Get**](docs/FakeApi.md#fakeInlineSchemaAnyofPath3Get) | **GET** /fake/inline/schema/anyof/path3 | 
 *FakeApi* | [**op1**](docs/FakeApi.md#op1) | **POST** /fake/api/changeowner | op1
 *FakeApi* | [**op2**](docs/FakeApi.md#op2) | **POST** /fake/api/changename | op2
 *FakeApi* | [**op3**](docs/FakeApi.md#op3) | **POST** /fake/api/query/enum | op3

samples/client/petstore/java/okhttp-gson-3.1/api/openapi.yaml

@@ -751,6 +751,47 @@ paths:
       - fake
       x-accepts:
       - application/json
+  /fake/inline/schema/anyof/path1:
+    get:
+      responses:
+        "200":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/myObject'
+          description: ""
+      tags:
+      - fake
+      x-accepts:
+      - application/json
+  /fake/inline/schema/anyof/path2:
+    get:
+      responses:
+        "200":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/myObject'
+          description: ""
+      tags:
+      - fake
+      x-accepts:
+      - application/json
+  /fake/inline/schema/anyof/path3:
+    get:
+      responses:
+        "200":
+          content:
+            application/json:
+              schema:
+                items:
+                  $ref: '#/components/schemas/myObject'
+                nullable: true
+          description: ""
+      tags:
+      - fake
+      x-accepts:
+      - application/json
 components:
   parameters:
     ref_to_uuid:
@@ -1074,6 +1115,8 @@ components:
     AllOfSimpleModel:
       allOf:
       - $ref: '#/components/schemas/SimpleModelWithArrayProperty'
+    myObject:
+      type: object
     updatePetWithForm_request:
       properties:
         name:

samples/client/petstore/java/okhttp-gson-3.1/docs/FakeApi.md

@@ -4,6 +4,9 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 | Method | HTTP request | Description |
 |------------- | ------------- | -------------|
+| [**fakeInlineSchemaAnyofPath1Get**](FakeApi.md#fakeInlineSchemaAnyofPath1Get) | **GET** /fake/inline/schema/anyof/path1 |  |
+| [**fakeInlineSchemaAnyofPath2Get**](FakeApi.md#fakeInlineSchemaAnyofPath2Get) | **GET** /fake/inline/schema/anyof/path2 |  |
+| [**fakeInlineSchemaAnyofPath3Get**](FakeApi.md#fakeInlineSchemaAnyofPath3Get) | **GET** /fake/inline/schema/anyof/path3 |  |
 | [**op1**](FakeApi.md#op1) | **POST** /fake/api/changeowner | op1 |
 | [**op2**](FakeApi.md#op2) | **POST** /fake/api/changename | op2 |
 | [**op3**](FakeApi.md#op3) | **POST** /fake/api/query/enum | op3 |
@@ -13,6 +16,174 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 | [**responseRefToRef**](FakeApi.md#responseRefToRef) | **GET** /ref/ref |  |
 
 
+<a id="fakeInlineSchemaAnyofPath1Get"></a>
+# **fakeInlineSchemaAnyofPath1Get**
+> Object fakeInlineSchemaAnyofPath1Get()
+
+
+
+### Example
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.FakeApi;
+
+public class Example {
+  public static void main(String[] args) {
+    ApiClient defaultClient = Configuration.getDefaultApiClient();
+    defaultClient.setBasePath("http://petstore.swagger.io/v2");
+
+    FakeApi apiInstance = new FakeApi(defaultClient);
+    try {
+      Object result = apiInstance.fakeInlineSchemaAnyofPath1Get();
+      System.out.println(result);
+    } catch (ApiException e) {
+      System.err.println("Exception when calling FakeApi#fakeInlineSchemaAnyofPath1Get");
+      System.err.println("Status code: " + e.getCode());
+      System.err.println("Reason: " + e.getResponseBody());
+      System.err.println("Response headers: " + e.getResponseHeaders());
+      e.printStackTrace();
+    }
+  }
+}
+```
+
+### Parameters
+This endpoint does not need any parameter.
+
+### Return type
+
+**Object**
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/json
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** |  |  -  |
+
+<a id="fakeInlineSchemaAnyofPath2Get"></a>
+# **fakeInlineSchemaAnyofPath2Get**
+> Object fakeInlineSchemaAnyofPath2Get()
+
+
+
+### Example
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.FakeApi;
+
+public class Example {
+  public static void main(String[] args) {
+    ApiClient defaultClient = Configuration.getDefaultApiClient();
+    defaultClient.setBasePath("http://petstore.swagger.io/v2");
+
+    FakeApi apiInstance = new FakeApi(defaultClient);
+    try {
+      Object result = apiInstance.fakeInlineSchemaAnyofPath2Get();
+      System.out.println(result);
+    } catch (ApiException e) {
+      System.err.println("Exception when calling FakeApi#fakeInlineSchemaAnyofPath2Get");
+      System.err.println("Status code: " + e.getCode());
+      System.err.println("Reason: " + e.getResponseBody());
+      System.err.println("Response headers: " + e.getResponseHeaders());
+      e.printStackTrace();
+    }
+  }
+}
+```
+
+### Parameters
+This endpoint does not need any parameter.
+
+### Return type
+
+**Object**
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/json
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** |  |  -  |
+
+<a id="fakeInlineSchemaAnyofPath3Get"></a>
+# **fakeInlineSchemaAnyofPath3Get**
+> List&lt;Object&gt; fakeInlineSchemaAnyofPath3Get()
+
+
+
+### Example
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.FakeApi;
+
+public class Example {
+  public static void main(String[] args) {
+    ApiClient defaultClient = Configuration.getDefaultApiClient();
+    defaultClient.setBasePath("http://petstore.swagger.io/v2");
+
+    FakeApi apiInstance = new FakeApi(defaultClient);
+    try {
+      List<Object> result = apiInstance.fakeInlineSchemaAnyofPath3Get();
+      System.out.println(result);
+    } catch (ApiException e) {
+      System.err.println("Exception when calling FakeApi#fakeInlineSchemaAnyofPath3Get");
+      System.err.println("Status code: " + e.getCode());
+      System.err.println("Reason: " + e.getResponseBody());
+      System.err.println("Response headers: " + e.getResponseHeaders());
+      e.printStackTrace();
+    }
+  }
+}
+```
+
+### Parameters
+This endpoint does not need any parameter.
+
+### Return type
+
+**List&lt;Object&gt;**
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/json
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** |  |  -  |
+
 <a id="op1"></a>
 # **op1**
 > Object op1()